Drug dependency is extremely difficult to escape. This is true whether the dependency is one based on ethanol, amphetamine, barbiturates, benzodiazepines, cocaine, nicotine, opioids, and phencyclidine or the like. There is thus a need for an agent decreasing or overcoming such addiction and, if possible reducing or eliminating the symptoms related to the withdrawal of such drugs or substances of abuse.
Different classes of neuronal receptors and neurotransmitters in the brain have been implicated in the complex mechanisms underlying for example the compulsive drinking of alcohol. Experimental findings have favoured the opioid, dopaminergic, serotonergic, and benzodiazepine receptor subtypes.
Based upon a large number of genetic and pharmacological studies, serotonin (5-HT) containing neurones in the limbic-midbrain and limbic-forebrain pathways are seemingly involved, in part, in the fundamental mechanisms underlying for example alcohol drinking.
Buspirone (The Merck Index 11th Ed., No. 1493), a partial 5-HT1A agonist, has been found to be effective for the treatment of anxiety. Buspirone was reported to attenuate significantly the consumption of alcohol by monkeys. In a clinical trial comparing buspirone to placebo in alcohol-dependent individuals, there was a lower drop-out rate in the buspirone-treated group, which also reported fewer signs of craving.
Amperozide (The Merck Index 11th Ed., No. 612), a 5-HT2 antagonist, was reported to significantly attenuate the intake of alcohol in rats without affecting neither consumption of food nor level of body weight (Myers et al., Pharmacol. Biochem. Behav. 43:661-667, 1992). Also the bisphenylalkyl-2-pyridinyl-piperazine derivative FG5893 was reported to have a similar amperozide-like action (Singh et al., Alcohol 10:243-248, 1993).